This invention relates to ring binders used for holding hole punched paper and the like, and more particularly, to a ring binder employing a dual angle ring metal which prevents unintended or accidental opening of the ring binder but which allows the binder to be readily opened and closed when desired.
Ring binders hold and store punched sheets of paper and other suitably hole punched materials. A locking/release mechanism commonly used in ring binders includes a thumb or finger operated latch located at each end of the mechanism. A pair of latch plates extend lengthwise of the ring binder and binder ring halves are attached to each plate at spaced intervals along the length of the binder. When a user presses against a latch, the respective plates are rotated relative to each other to pull apart (open) the binder rings so paper can then be inserted or removed from the binder. The user then presses against the separated sections of a binder ring to snap or push them together and close the binder.
Current locking mechanisms have certain drawbacks. One of these is referred to as "sponginess" which is, in effect, a soft opening of the ring binder. The latch plates are covered by a shield extending lengthwise of the binder and having spaced openings for the respective binder ring halves to extend through the shield. This shield is made of a spring metal. When the binder is closed, the latch plates are at an angle to each other. Movement of paper from one side of the binder to the other causes a force to be exerted on the binder ring halves on one side of the binder and this force is transmitted to the latch plates. In consequence, the latch plates rotate relative to each other in a binder opening direction. They will continue to do so until the plates reach a position where they exert a force on each other which prevents their further opening movement. The amount of plate travel, and consequent binder ring opening produces a soft or spongy effect in that there is not a solid closure of the binder at all times. The "sponginess" can sometimes result in inadvertent opening of the binder and spillage of its contents. The present invention addresses this problem and provides a solution to it.